I. Field of the Invention
The present invention relates to implantable devices used to stimulate the heart to control the heart's rhythm. This invention is more specifically directed toward the connection between a cardiac rhythm management device such as an implantable pacemaker or defibrillator and a lead adapted to be implanted in the coronary veins on the left side of the heart.
II. Description of the Prior Art
As set forth in U.S. Pat. No. 5,803,928 granted on Sep. 8, 1998 to Tockman et al, important health advantages are achieved by positioning an electrode in a branch of the great vein of the heart for the purpose of stimulating the left ventricle. Such an electrode can, for example, be used to treat tachycardia. Such an electrode can also be used to treat heart failure.
Traditional leads are not designed to be implanted in the great vein. The leads, themselves, tend to be too big and inflexible to be advanced through the coronary sinus and into the great vein of the heart. These size and flexibility problems are compounded if one would try to implant the lead in this area using traditional stylets, guidewires and guide catheters given the size and flexibility of such equipment. To successfully implant the lead in the vasculature of the left side of the heart, both the lead and the equipment used to implant the lead should be smaller in diameter.
Successful treatment of tachycardia or heart failure can often best be achieved by stimulating different areas of the heart in a controlled and precisely timed manner. Thus, most cardiac rhythm management devices have a plurality of ports to which leads can be attached. Over the years, the port arrangement and the manner in which the leads are attached to the port have become standardized. Several significant problems exist, however, if this standard arrangement is used to secure a left-sided access lead to a cardiac rhythm management device.
For example, a guide catheter small enough to be useful in positioning the lead cannot be used with a lead having a standard connector arrangement because the connector arrangement of the lead is too large to permit the guide catheter to be removed. Also, if a standard connector arrangement is used, the left-sided lead could be mistakenly secured to the wrong port resulting in the improper delivery of pulses to the heart.